Output assemblers (indra_world.assemblers)

As opposed to INDRA, the importance of output/model assemblers in INDRA World is minor, since other systems such as Delphi (https://github.com/ml4ai/delphi) and DySE (https://dl.acm.org/doi/10.1145/3359115.3359123) take on the role of converting assembled INDRA Statements into probabilistic and logical dynamical models, respectively.